I've managed to engineer a much healthier lifestyle for myself using quantified self techniques. My quality of life has improved significantly, and I went from being a C student to an A+ student and a far more effective scientist/engineer.

For one, I discovered I focus better and get more work done if I avoid gluten. It's not placebo controlled, but my real productivity is significantly higher, as measured by hours of focused work completed per day. I feel sick with a "brain fog" and malaise when I eat gluten, and I seem to have felt that way continuously for my entire life until I experimented with removing it.

Additionally, I have been able to consistently get a much better nights sleep by analyzing data with my Zeo EEG and correlating against various behaviors. I've found specific habits that improve sleep and consistently stick with them. For the most part I suspected that things like maintaining a consistent sleep schedule, turning off the lights early, taking melatonin, and avoiding caffeine in the afternoon would improve my sleep but I didn't suspect that the effect would be so strong that failing to stick to those would have massive negative effects that last for days.

Also, I've discovered that food reward is the main variable influencing my hunger, and by sticking to a low food reward diet I can maintain a healthy weight about 50lbs less than my previous weight effortlessly- without being hungry.

It's hard to isolate placebo from other effects in quantified self experiments, but in some cases that may not be necessary. I want to know the real truth as much as anybody, but if a given behavior causes a measurable improvement in my productivity or quality of life that lasts, then it's worth doing even if it's a placebo.

I'd go so far as to say that my self-experimentation has resulted in the unusual sensation of aging in reverse: as I learn more about my own body and how to make it function better I am continuously becoming healthier and more fit than I ever have been before.

It's a snowball effect especially since I'm a bioengineering grad student researching ways to optimize human health: as I become healthier and more able to focus and work productively, I discover more and more ways of improving my own health which result in even better focus and even more productive work. I don't know how sustainable this trend is, but I'm going to find out.